Method for the operation of a drivetrain

ABSTRACT

A method for operating a motor vehicle drivetrain with at least an automatic transmission and a drive motor. The automatic transmission includes at least five shifting elements to transmit torque and/or power. In each forward and reverse gear a maximum of two shifting elements are disengaged while the remaining shifting elements are engaged. Two consecutive gearshifts are carried out through selection of the five shifting elements. During a first gearshift, implemented as a multiple gearshift, a subsequent second gearshift, implemented as either a single or multiple gearshift, is prepared. During the first gearshift, a first shifting element is disengaged, a second shifting element is engaged, a third shifting element is prepared for disengagement in a subsequent second gearshift and a fourth shifting element is prepared for engagement. Further, during the first gearshift and the subsequent second gearshift, a fifth shifting element is retained in at least a substantially engaged state.

This application claims priority from German Application Serial No. 102006 026 604.8 filed Jun. 8, 2006.

FIELD OF THE INVENTION

The invention relates to a method for operating a motor vehicledrivetrain comprising at least one automatic transmission and one drivemotor.

BACKGROUND OF THE INVENTION

The main components of a motor vehicle drivetrain are a drive motor anda transmission. A transmission converts torques and speeds and sotransforms the traction force provided by the drive motor. The presentinvention concerns a method for the operation of a drivetrain whichcomprises at least a drive motor and an automatic transmission. In thecontext of the present invention, the term “automatic transmission” isunderstood to mean any transmission that effects automatic gear changes,these also being known as variable speed transmissions.

From DE 100 35 479 A1, a method for operating an automatic transmissionis known in which successive upshifts and successive downshifts can becarried out with some overlap in order to improve the shift speed. Forthis, during each first upshift or downshift, a shift element needed forthe subsequent second upshift or downshift is prepared, while the firstupshift or downshift is in progress, in such manner that when asynchronization point is reached, namely a synchronous speed of thefirst upshift or downshift in progress, the subsequent second upshift ordownshift can be carried out immediately.

In this way, according to DE 100 35 479 A1, single shifts are overlappedwith one another, which means that each first upshift or downshiftcarried out and each subsequent second upshift or downshift is a singleshift between two directly successive gears.

The method known from DE 100 35 479 A1 can be used for an automatictransmission with five shift elements of which, two shift elements areengaged for transmitting torque and/or transmitting power in one forwardgear and one reverse gear and three shift elements are disengaged. Suchan automatic transmission can be used to implement six forward gears. Inthe development of automatic transmissions, a trend toward anever-greater number of gears, particularly for the forward gears of anautomatic transmission, can be observed. Presently, for example,automatic transmissions with eight forward gears and one reverse gearare under development, wherein such automatic transmissions have atleast five shift elements such that, for torque or force transfer atleast five shift elements are disengaged in one forward gear and onereverse gear and the remaining shift elements are engaged. The methodknown from DE 100 35 479 A1 is not suited for such an automatictransmission.

Starting from this, the present invention addresses the problem ofproviding a new type of method for the operation of a drivetraincomprising at least an automatic transmission and a drive motor.

SUMMARY OF THE INVENTION

According to the first embodiment of the invention, in an automatictransmission with at least five shift elements of which, for torque orforce transfer in any forward gear and in a reverse gear, no more thantwo shift elements are disengaged and the remaining shift elements areengaged. Two respective consecutive upshifts or two respectiveconsecutive downshifts can be carried out by selecting at least fiveshift elements in that:

a) a first upshift or downshift is carried out as a multiple gearshiftwhere, during the current first upshift or downshift, a single gearshiftor a multiple gearshift is prepared as a subsequent second upshift ordownshift;

b) when performing the first upshift or downshift as a multiplegearshift, a first shift element of the automatic transmission is openedand thus disengaged and a second shift element of the automatictransmission is closed and thus engaged;

c) while performing the first upshift or downshift as a multiplegearshift for the subsequent second upshift or downshift, a third shiftelement of the automatic transmission is prepared for opening and thusdisengagement and a fourth shift element of the automatic transmissionis prepared for closure and thus engagement;

d) while the first upshift or downshift is carried out and while thesecond upshift or downshift is carried out, at least a fifth shiftelement is maintained in the engaged or substantially engaged state.

According to a second embodiment of the invention, in an automatictransmission comprising at least five shift elements of which, fortorque or force transfer in any forward gear and in a reverse gear, amaximum of two shift elements are disengaged and the remaining shiftelements are engaged. A shift element that engages during the secondupshift or downshift is prepared for engagement in a subsequent secondupshift or downshift at a time while a first upshift or downshift isperformed, which time precedes the point at which the synchronous pointof the current first upshift or downshift is reached by atime-controlled or event-controlled applicable first period.

According to a third embodiment of the invention, in an automatictransmission with at least five shift elements of which, for torque orforce transfer in any forward gear and a reverse gear, a maximum of twoshift elements are disengaged and the remaining shift elements areengaged, while performing a first upshift or downshift and/or whileperforming a subsequent second upshift or downshift a torque of thedrive motor is increased and/or reduced in relation to a torque for thedrive motor derived from input provided by the driver in order tosupport the overlapped consecutive upshifts or downshifts.

These three embodiments, according to the invention outlined above, canbe used for the operation of a drivetrain either alone or in acombination of two embodiments or in a combination of all threeembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with referenceto the accompanying drawings in which:

FIG. 1 is a drivetrain diagram of a motor vehicle;

FIG. 2 is a gearshift pattern of an automatic transmission of thedrivetrain with five shift elements;

FIG. 3 is a shift element matrix for the shift elements of the gearshiftpattern, according to FIG. 2, to illustrate which shift elements areengaged in what gear, and

FIG. 4 is a diagram to illustrate the method according to the inventionfor operating a drivetrain of a motor vehicle, comprising an automatictransmission, according to FIGS. 2 and 3.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic representation of a drivetrain of a motor vehicle,the drivetrain comprising a drive motor 1, an automatic transmission 2and a drive wheel 3 of the motor vehicle. The automatic transmission 2transfers the traction force produced by the drive motor 1 to the wheels3 of the motor vehicle.

According to FIG. 1, when the drivetrain is operated in traction mode,power flows in the direction of arrow 4 from the drive motor 1 towardthe wheels 3 of the motor vehicle. In contrast, if the drivetrain isoperated in thrust mode, for example when braking or coasting, the powerflow is in the direction of arrow 5, from the wheels 3 toward the drivemotor 1.

The invention relates to a method for operating a drivetrain comprisingthe drive motor 1 and the automatic transmission 2, where the automatictransmission 2 has at least five shift elements and where, for torque orforce transfer, a maximum of two shift elements in a forward gear, aswell as in a reverse gear, are disengaged and the remaining shiftelements are engaged. An example of such an automatic transmission isshown in FIGS. 2 and 3. While the invention is described more closelyhereinafter based on this example, it is not limited in its use to thisexample of an automatic transmission.

FIG. 2 shows a gearshift pattern 6 of the automatic multi-ratiotransmission 2, which has four transmission gearsets 7, 8, 9 and 10 inorder to convert a transmission input torque present on a transmissioninput 11 to a transmission output torque on a transmission output 12.

The transmission gearsets 7, 8, 9 and 10 of the automatic transmission 2are configured as planetary transmission gearsets according to FIG. 2.According to the gearshift pattern 6 from FIG. 2, in addition to thefour transmission gearsets 7-10, the automatic transmission alsocomprises five shift elements 13, 14, 15, 16 and 17. Shift element 13 isalso referred to as shift element A; shift element 14 as shift elementB; shift element 15 as shift element C; shift element 16 as shiftelement D, and shift element 17 as shift element E. Shift element A andB are each brakes and shift elements C, D and E are clutches.

For the automatic transmission represented schematically in FIG. 2,comprising the five shift elements 13-17, eight forward gears, as wellas one reverse gear, can be implemented using a shifting matrix 18,shown according to FIG. 4 where, in the left-hand column of the shiftingmatrix 18, the eight forward gears “1” to “8”, as well as the reversegear “R”, have been entered and the shift elements A to E have beenentered in the first line of the shifting matrix 18. Shift elements thatare marked with a dot in the shift element matrix 18 are engaged in therespective gear. In each forward gear, as well as in the reverse gear,accordingly, three of the five shift elements are engaged for thetransmission of power from the transmission input 11 to the transmissionoutput 12. For example, shift elements A, B and C are engaged forforward gear “1” and shift elements A, B and D are engaged for thereverse gear “R”. The remaining shift elements are disengaged in therespective gear.

To improve the shifting speed, successive upshifts or consecutivedownshifts are carried out with some overlap, such that during a firstupshift or downshift at least one shift element needed for thesubsequent second upshift or downshift is prepared while the firstupshift or downshift, specifically such that upon reaching a synchronouspoint of the current first upshift or downshift the subsequent secondupshift or downshift can be carried out immediately.

The Table below shows the possible overlapped downshifts as well as thepossible overlapped upshifts for the automatic transmission 2 accordingto FIGS. 2 and 3 in the left-hand column, where an additional downshiftor upshift listed in parenthesis in the left-hand column behind adownshift or upshift means that the upshift or downshift not inparenthesis is the first downshift or upshift and the downshift orupshift in parenthesis is the second downshift or upshift for which theshift elements are prepared during the current first downshift orupshift.

SHIFT ELEMENTS A B C D E DOWNSHIFT 8-6 (6-5) d pe e x pd 7-5 (5-4) d epd x pe 5-3 (3-2) pe x pd d e 4-2 (2-1) e x pe d pd 8-4 (4-3) d e pe pdx 8-2 (2-1) x e pe d pd 6-3 (3-2) pe e pd d x 7-5 (5-3) d e x pd pe 6-4(4-2) pe e d pd x UPSHIFT 1-3 (3-4) d x pd pe e 2-4 (4-5) d x pe e pd4-6 (6-7) pe d e x pd 5-7 (7-8) e d pd x pe

In the Table, shift elements that are closed and thus engaged during afirst upshift or downshift to be performed have been marked with “e”.However, shift elements that are opened and thus disengaged during afirst upshift or downshift have been marked with “d” in the above Table.Shift elements that during a first upshift or downshift are prepared forclosure and thus engagement or for opening and thus disengagement in asubsequent second upshift or downshift have been marked with “pe” or“pd” in the above Table. Shift elements marked with “x” are and remainengaged during an upshift or downshift.

When using the above Table for the automatic transmission, according toFIGS. 2 and 3, multiple gearshifts are performed as a function of agearshift change to be performed from an actual gear to a target gear,both as first upshifts and as first downshifts. While a multiplegearshift is carried out as a first upshift or downshift, a secondsubsequent upshift or downshift is prepared as either a single ormultiple gearshift.

First multiple downshifts, according to the Table above, are doubledownshifts or triple downshifts or quadruple downshifts or even sextupledownshifts. Optionally, subsequent second multiple downshifts are doubledownshifts.

A first multiple upshift is always a double upshift. A single upshiftcan be prepared as a second subsequent upshift during a first multipleupshift performed as a double upshift.

According to the first embodiment of the present invention, a firstshift element is opened and thus disengaged and a second shift elementis closed and thus engaged when carrying out a first upshift ordownshift as a multiple shift. While the first upshift or downshift iscarried out as a multiple gearshift, a third shift element is preparedfor opening and thus disengagement and a fourth element for closure andthus engagement for the subsequent second upshift or downshift, which isprepared as a single gearshift or multiple gearshift and is optionallycarried out. While the first upshift or downshift is carried out andwhile the second upshift or downshift is carried out, at least a fifthshift element is maintained in the engaged or substantially engagedstate.

This first embodiment of the present invention is described withreference to FIG. 4 based on the example of two consecutive downshifts.The first downshift is carried out as a multiple gearshift, namely as adouble gearshift. The second downshift is being prepared as a singleshift while the first downshift is carried out. According to the Tableabove, the overlapped downshifts can be, for example, 7-5 (5-4) or also4-2 (2-1).

FIG. 4 shows the courses of different signals over time, where signalline 19 represents a desired gear as a function of input provided by thedriver; wherein signal line 20 represents a target gear determined onthe basis of the desired gear; where signal line 21 represents an actualgear; where signal line 22 represents the torque of the drive motor 1 ofthe drivetrain, and signal line 23 represents a rotational speed of thedrive motor 1.

Signal lines 24, 25, 26, 27 and 28 represent the selection and/or thebehavior over time of five shift elements conducting two consecutivedownshifts in an overlapped manner, where the signal line 24 representsthe behavior over time of a first shift element to be opened and thusdisengaged in the first downshift; where the signal line 25 representsthe behavior over time of the second shift element to be closed and thusengaged in the first downshift; where the signal line 26 represents thebehavior over time of the third shift element prepared during the firstdownshift for opening and thus disengagement in the subsequent seconddownshift, and where signal line 27 represents the behavior over time ofthe fourth shift element during the first downshift for closure and thusengagement in a subsequent second downshift. Signal line 28 representsthe behavior, over time, of a fifth shift element, which is maintainedin the engaged or substantially engaged state while the first upshift ordownshift is performed and while the second upshift or downshift isperformed.

At the time A, a change of the desired gear (see signal line 19) and,derived from that, a change of the target gear (see signal line 20) byway of a desired multiple downshift by two gears (x-2), exists wherethis triggers the overlapped implementation or preparation ofconsecutive downshifts, specifically such that at the time A, on onehand, the first shift element (see signal line 24) to be opened and thusdisengaged in the first downshift starts with the shifting phase andthat, on the other hand, the second shift element (see signal line 25)to be closed and thus engaged in the first downshift is subjected to arapid filling process, where the rapid filling takes place between timesA and B.

The third shift element (see signal line 26), which is to be preparedduring the first downshift, which is a multiple gearshift, for thesubsequent second downshift, which is a single gearshift, as well as thefourth shift element (see signal line 27) are set to a defined state attime A. The fifth shift element (see signal line 28) is kept engaged.

After completing the rapid filling step of the second shift element (seesignal line 25) to be closed and thus engaged in the first downshift,the second shift element transitions from the rapid filling phase to afilling equalization phase, where the filling equalization phase extendsbetween times B and D. The rapid filling phase between times A and B andthe filling equalization phase between times B and D, together definethe filling phase of the second shift element that is to engage duringthe first downshift. At time D, the second shift element (see signalline 25) to be closed and thus engaged in the first downshift istransferred from the filling phase to the shifting phase.

While the first downshift is carried out as a multiple gearshift duringwhich the first shift element, according to signal line 24, is openedand thus disengaged and the second shift element, according to signalline 25, is closed and thus engaged. Two shift elements are prepared fora possible following second downshift which, in the example, is to beperformed as a single gearshift.

At time C, therefore, the fourth shift element (see signal line 27) tobe closed and thus engaged in possibly a following second downshift isprepared with a rapid filling phase, which extends between times C andE.

With the completion of the rapid filling phase of the fourth shiftelement at time E, this element switches to a filling equalization phasewhich, according to FIG. 4, lasts until time G. At time G, the fourthshift element prepared for engagement switches from the filling phase tothe shifting phase.

Likewise, while the first downshift is being performed, the third shiftelement (see signal line 26) is prepared for opening and disengagementin a subsequent second downshift. At time F, a transition phase of thethird and hence disengaging shift element preparing for the subsequentsecond downshift is started where, at time S which corresponds to asynchronous point of the first downshift, a change occurs from the firstdownshift to the subsequent second downshift.

Upon reaching time S, the shift elements that were being prepared duringthe first downshift become the active shift elements of the subsequentsecond downshift. Thus at time G, the fourth shift element, which wasprepared for closure and thus engagement during the first downshift,becomes the engaging shift element of the second downshift. The firstshift element, which was disengaged and thus opened during the firstdownshift, is therefore disconnected. Starting at time H, the thirdshift element, which was being prepared for opening and thusdisengagement, reaches the disengagement pressure level.

The fifth shift element (see signal line 28) is kept engaged orsubstantially engaged while the first downshift is performed and whilethe second downshift is performed.

During the subsequent second downshift, shift elements are prepared forpossibly a following third downshift, which is, in turn, a singledownshift (see signal lines 29 and 30).

According to the second embodiment of the present invention, the fourthshift element (see signal line 27) to be engaged during the seconddownshift is prepared for engagement in the second downshift at the timeC, while the first downshift is being performed, with a rapid fillingphase, which time precedes the point at which the synchronous point ofthe current first downshift at time S is reached by a time-controlled orevent-controlled applicable first time period T₁. The time-controlled orevent-controlled applicable first time period T₁ can be implemented, forexample, by a time reserve or a speed differential, relative tosynchronous point S of the first downshift.

When time C resulting from synchronous point S and the applicable firsttime period T₁, as FIG. 4 shows, follows the end of the rapid fillingphase of the second shift element (see signal line 25) to be engaged inthe first downshift, meaning after time B, the preparations of thefourth shift element (see signal line 27) to be engaged in the seconddownshift are started promptly.

On the other hand, if the time C, resulting from the synchronous point Sof the current first downshift and from the applicable first time periodT₁, should precede the end (time B) of the rapid filling phase of thesecond shift element to be engaged in the first downshift, thepreparation of the fourth shift element is delayed until the rapidfilling phase of the second shift element to be engaged in the firstdownshift has been completed.

As mentioned above, the fourth shift element (see signal line 27)prepared for engagement in the second downshift while the firstdownshift is being performed is switched from the preparation phase tothe shifting phase at time G.

This time G precedes the synchronous point S of the first downshift by atime-controlled or event-controlled applicable second time period T₂. AsFIG. 4 shows, when time G, resulting from the synchronous point S of thefirst downshift and the applicable second time period T₂, follows theend of the rapid filling phase (time E) of the fourth shift element tobe engaged in the second downshift, the fourth shift element to beengaged in the second downshift is switched directly from thepreparation phase to the shifting phase.

On the other hand, if time G, resulting from the synchronous point S ofthe current first downshift and the applicable second time period T₂,should precede the end of the rapid filling phase (time E) of the fourthshift element to be engaged in the second downshift, the transition ofthe fourth shift element from the preparation phase to the shiftingphase is delayed until the rapid filling phase of the fourth shiftelement has been completed.

As mentioned above, the third shift element, which is prepared foropening and thus disengagement in the subsequent second downshift whilethe first downshift is being carried out, is shifted from thepreparation phase to the shifting phase at time F, where time F precedesthe time at which the synchronous point S of the first downshift isreached by a time-controlled or event-controlled applicable third timeperiod T₃.

At time F, a decision is made in the illustrated embodiment as towhether the second downshift prepared during the first downshift is, infact, implemented.

In this way, a prepared subsequent shift is carried out only if thiscorresponds to the input provided by the driver. As FIG. 4 shows, attime F, according to the signal line 19 representing the driver's input,a further downshift (x-3) is requested for the desired gear so that thesecond downshift is then, in fact, implemented in the example accordingto FIG. 4.

As explained above, during the second downshift, the corresponding shiftelements, according to signal lines 29 and 30, are prepared for a thirdsubsequent downshift where, in FIG. 4, for the third downshift to beprepared during the second downshift, the corresponding applicable firsttime period T′₁, second time period T′₂ and third time period T′₃ relateto a synchronous point S′ of the second downshift. The third downshiftthat is prepared, while the second downshift is being performed, is asingle downshift.

FIG. 4 illustrates that at a time, defined by the synchronous point S′of the second downshift and the applicable third time period T′₃, nofurther downshift is desired for the desired gear based on the signalline 19 representing the driver's input so that the third downshiftprepared during the second downshift is not carried out, but instead isaborted.

As FIG. 4 shows, according to the signal line 21, the actual gear is setto a new value as the synchronous point S or S′ of an implementedgearshift is detected, while the target gear, according to the signalline 20, changes to the next gear or remains unchanged as a function ofthe desired gear, according to signal line 19.

According to a third embodiment of the present invention, for theexemplary embodiment shown according to FIG. 4, torque of the drivemotor is increased or reduced in relation to the torque of the drivemotor derived from input provided by the driver, while the firstdownshift is performed and while the second downshift is performed, inorder to support the overlapped implementation of the consecutivedownshifts. For example, signal line 22, shown as a solid line accordingto FIG. 4, corresponds to torque of the drive motor derived from inputprovided by the driver. According to a first variation, shown with adash-dotted line according to FIG. 4, the torque of the drive motor isincreased in relation to the torque for the drive motor derived from thedriver's input while the first downshift is carried out as well as whilethe second downshift is carried out. According to a second variationshown with a dotted line according to FIG. 4, the torque of the drivemotor is reduced in relation to the torque for the drive motor derivedfrom the driver's input toward the end of the second downshift. Bothvariants will be addressed in detail hereinafter.

The excess increase of the torque of the drive motor in relation to thetorque of the drive motor derived from the driver's input which increaseis illustrated with a dash-dotted line in FIG. 4, is carried out whenthe drivetrain is operated either in a trailing throttle operation or ina partial load traction mode. During each downshift that is carried out,both in the trailing throttle operation and in the partial load tractionmode, a torque increase of the drive motor, in relation to the torquederived from the driver's input, is carried out, while a verificationstep is performed during each downshift to ensure that a preparedsubsequent downshift corresponds to the driver's input. This occurs at atime that depends on the synchronous point S and on the applicable thirdtime period T₃, meaning in the exemplary embodiment according to FIG. 4at time F.

At that time, based on the driver's input, when a subsequent downshiftis requested, a shift from the torque increase of the first downshift tothe torque increase of the second downshift is carried out where, in theillustrated example, the torque increase of the second downshift isgreater than the torque increase of the first downshift. Unlike in thisexample, it is also possible that the torque increase of the seconddownshift is smaller than the torque increase of the first downshift.Likewise, both torque increases can be equal. It is preferable if aramp-like transition is carried out between the two torque increases.

At the time referred to above, which time is defined by the synchronouspoint S and the applicable third time period T₃, based on the driver'sinput, if a subsequent downshift is not desired, the prepared subsequentdownshift is aborted and the torque increase for the drive motor isterminated to end the shifting process. This is illustrated, accordingto FIG. 4, for the third downshift that is under preparation during thesecond downshift.

In the execution, as well as the preparation of consecutive downshiftsin a traction mode of the drivetrain, during each downshift that isperformed, in turn, a verification is performed again at atime-controlled or event-controlled applicable time, namely, at the timedependent on the synchronous point S and the applicable third timeperiod T₃, as to whether a prepared subsequent gearshift corresponds tothe driver's input. If this is not the case, as is illustrated accordingto FIG. 4, for the third downshift that is under preparation during thesecond downshift, the prepared subsequent downshift is aborted and, inorder to end the shifting process in the traction mode, the torquereduction for the drive motor, which is shown with a dotted signal line22 according to FIG. 4, is performed in relation to the torque derivedfrom the driver's input.

At this time, however, if a subsequent downshift is desired, as is thecase according to FIG. 4, for the second downshift that is underpreparation during the first downshift, the torque reduction of thedrive motor is not carried out. The torque reduction during downshiftsis consequently implemented only when a shifting process is supposed tobe ended, meaning no subsequent gearshift follows. Furthermore, thetorque reduction, referred to above, is carried out only in tractionmode, both with a wide-open throttle and in partial load. In thetrailing throttle operation, however, this torque reduction is notimplemented with downshifts.

In the exemplary embodiment according to FIG. 4, two consecutivedownshifts can be implemented as overlapped gearshifts by selecting fiveshift elements where, according to FIG. 4, for the implementation of thefirst downshift as a multiple gearshift, a first shift element (signalline 24) is opened and thus disengaged and a second shift element(signal line 25) is closed and thus engaged. While the first downshiftis carried out, the third shift element (signal line 26) is prepared foropening and thus disengagement in the subsequent second downshift, andthe fourth shift element (signal line 27) is prepared for closure andthus engagement. The fifth shift element (signal line 28) is keptengaged or substantially engaged while the first downshift is performedand while the second downshift is performed.

The procedure for overlapped downshifts, according to the inventionaccording to FIG. 4, can be translated in an equivalent fashion tooverlapped upshifts. In the implementation of consecutive upshifts, theonly difference as compared with the implementation of consecutivedownshifts, according to FIG. 4, exists with respect to the third aspectof the present invention, which relates to the increase or decrease ofthe torque of the drive motor in relation to the torque for the drivemotor derived from the driver's input.

For consecutive upshifts in a trailing throttle operation of thedrivetrain, a torque increase is carried out for both upshifts while, inthe traction mode, a torque reduction is carried out in both upshifts. Atorque reduction for ending the shifting process does not occur withconsecutive upshifts.

The method according to the invention, can be used with all automatictransmissions comprising at least five shift elements and where, fortorque transmission and/or power transmission purposes, a maximum of twoof these at least five shift elements are disengaged and the remainingshift elements are engaged.

REFERENCE NUMERALS

1 drive motor 2 automatic transmission 3 wheel 4 arrow 5 arrow 6transmission layout 7 transmission gearset 8 transmission gearset 9transmission gearset 10 transmission gearset 11 transmission input 12transmission output 13 shift element A 14 shift element B 15 shiftelement C 16 shift element D 17 shift element E 18 shift element matrix19 signal line 20 signal line 21 signal line 22 signal line 23 signalline 24 signal line 25 signal line 26 signal line 27 signal line 28signal line 29 signal line 30 signal line

1. A method of operating of a drivetrain of a motor vehicle having atleast a drive motor and an automatic transmission with at least fiveshift elements, the method improving a shift speed of at least one of asuccessive upshift and a successive downshift, such that during a firstupshift or a first downshift, at least one shift element, required forthe respective successive upshift or the successive downshift, isprepared such that when a synchronization point of the first upshift orthe first downshift in progress is reached, the successive upshift orthe successive downshift can be immediately carried out, the methodcomprising the steps of: requiring, at most, two of the at least fiveshift elements to be disengaged and a remainder of the at least fiveshift elements to be engaged, in each of a plurality of forward andreverse gears, for transferring torque and force, and two respectiveconsecutive upshifts or two respective consecutive downshifts areaccomplished with at least some overlap; defining the first upshift andthe first downshift as a multiple gearshift; preparing the successiveupshift or the successive downshift during the first upshift or thefirst downshift, the successive upshift or the successive downshiftbeing one of a single gearshift or a multiple gearshift; disengaging afirst of the at least five shift elements and engaging a second of theat least five shift elements during the first upshift or the firstdownshift; preparing a third of the at least five shift elements, duringthe first upshift or the first downshift, for disengagement in thesuccessive upshift or the successive downshift; preparing a fourth ofthe at least five shift elements, during the first upshift or the firstdownshift, for engagement in the successive upshift or the successivedownshift; at least partially retaining at least a fifth of the at leastfive shift elements during the first upshift or the first downshift andduring the successive upshift or the successive downshift; and one ofincreasing and decreasing a torque of the drive motor, relative to atorque of the drive motor derived from a driver's wish, during at leastone of the first upshift or the first downshift and the successiveupshift or the successive downshift to assist in overlappedimplementation of the successive upshift or the successive downshift. 2.The method according to claim 1, further comprising the step ofpreparing the at least one shift element for a subsequent upshift or asubsequent downshift, during a previous upshift or a previous downshift,the subsequent upshift or the subsequent downshift only being performedif the subsequent upshift or the subsequent downshift corresponds toinput provided by a driver at one of a time-controlled applicable timeand an event-controlled applicable time.
 3. The method according toclaim 1, further comprising the step of preparing for engagement, duringthe first upshift or the first downshift, the at least one shift elementrequired for the successive upshift or the successive downshift, at atime which precedes the synchronous point of the first upshift or thefirst downshift by one of a time-controlled and an event-controlledapplicable first time period.
 4. The method according to claim 3,further comprising the step of changing the at least one shift element,prepared to be engaged during the successive upshift or the successivedownshift, from a preparation phase to a shift phase at a time beforereaching the synchronization point of the first upshift or the firstdownshift, by a second time interval applied in another time-controlledmanner or another event-controlled manner.
 5. The method according toclaim 4, further comprising the step of delaying the step of changingthe at least one shift element, prepared to be engaged during thesuccessive upshift or the successive downshift, from the preparationphase to the shift phase, until the rapid filling phase of the at leastone shift element to be engaged during the successive upshift or thesuccessive downshift has been completed, if the time before reaching thesynchronization point of the first upshift or the first downshift andthe second time interval occurs before the end of a rapid filling phaseof the at least one shift element to be engaged during the successiveupshift or the successive downshift; or immediately changing the atleast one shift element to be engaged during the successive upshift orthe successive downshift from the preparation phase to the shift phase.6. The method according to claim 3, further comprising the step ofdelaying the preparation of the at least one shift element to be engagedduring the successive upshift or the successive downshift, until a rapidfilling phase of a first shift element to be engaged during the firstupshift or the first downshift has been completed, if a time, determinedfrom the synchronization point of the first upshift or the firstdownshift in progress and the first time period, occurs before the endof the rapid filling phase of the first shift element to be engagedduring the first upshift or the first downshift; and immediatelybeginning preparation of the at least one shift element to be engagedduring the successive upshift or the successive downshift.
 7. The methodaccording to claim 3, further comprising the steps of preparing the atleast one shift element disengaging in the successive upshift or thesuccessive downshift while the first upshift or downshift is carriedout, for disengaging during the successive upshift or the successivedownshift at the beginning of the first upshift or downshift, andswitching the at least one shift element prepared for disengaging in thesuccessive upshift or the successive downshift from a preparation phaseto a shifting phase at the time that precedes the synchronous point ofthe first upshift or the first downshift by a time-controlled orevent-controlled applicable third time period.
 8. The method accordingto claim 1, further comprising the step of checking, during eachdownshift carried out and at a time, applicable in a time-controlledmanner or an event-controlled manner, whether a prepared follow-upshift, corresponds with a driver's wish to carry out further successivedownshifts during traction operation of the drivetrain, if no follow-upshift is desired, the prepared follow-up shift is discontinued and thetorque of the drive motor torque is reduced relative to the torque ofthe drive motor derived from the driver's wish, but if a follow-up shiftis desired, on the basis of the driver's wish, the prepared follow-upshift is carried out and the torque of the drive motor is not reduced.9. The method according to claim 1, further comprising the step ofincreasing the torque of the drive motor relative to torque of the drivemotor, derived from the driver's wish, during each downshift carried outand also checking, during each downshift carried out and at the timeapplicable in a time-controlled manner or an event-controlled manner,whether a prepared follow-up shift corresponds to the driver's wish, tocarry out a follow-up downshifts when the drivetrain is in a thrustoperation or a part-load traction operation, if the follow-up downshiftis desired, a ramp-like transition, is implemented between torque levelsof the follow-up downshifts, but if the follow-up shift is not desired,the prepared follow-up shift is discontinued and the torque of the drivemotor is discontinued to prevent the follow-up downshift.
 10. The methodaccording to claim 1, further comprising the steps of reducing thetorque of the drive motor relative to the torque derived from thedriver's wish, during traction operation of the drivetrain to carry outthe successive upshifts; and increasing the torque of the drive motorrelative to the torque derived from the driver's wish, during each ofthe successive upshifts carried out to carry out the successive upshiftsduring thrust operation of the drivetrain.
 11. A method of operating adrivetrain of a motor vehicle having at least a drive motor and anautomatic transmission with only five shift elements, the methodimproving a shift speed of at least one of a successive upshift and asuccessive downshift, such that during a first upshift or a firstdownshift, at least one shift element, required for the respectivesuccessive upshift or the successive downshift, is prepared such thatwhen a synchronization point of the first upshift or the first downshiftin progress is reached, the successive upshift or the successivedownshift can be immediately carried out, the method comprising thesteps of: requiring, at most, two of the five shift elements to bedisengaged and a remainder of the five shift elements to be engaged, ineach of a plurality of forward and reverse gears, for transferringtorque and force, and two respective consecutive upshifts or tworespective consecutive downshifts are accomplished with at least someoverlap; defining the first upshift and the first downshift as amultiple gearshift; preparing the successive upshift or the successivedownshift during the first upshift or the first downshift, thesuccessive upshift or the successive downshift being one of a singlegearshift or a multiple gearshift; disengaging a first of the five shiftelements and engaging a second of the five shift elements during thefirst upshift or the first downshift; preparing a third of the fiveshift elements, during the first upshift or the first downshift, fordisengagement in the successive upshift or the successive downshift;preparing a fourth of the five shift elements, during the first upshiftor the first downshift, for engagement in the successive upshift or thesuccessive downshift; and at least partially retaining at least a fifthof the five shift elements during the first upshift or the firstdownshift and during the successive upshift or the successive downshift.12. The method according to claim 11, further comprising the step ofpreparing the at least one shift element for a subsequent upshift or asubsequent downshift, during a previous upshift or a previous downshift,the subsequent upshift or the subsequent downshift only being performedif the subsequent upshift or the subsequent downshift corresponds toinput provided by a driver at one of a time-controlled applicable timeand an event-controlled applicable time.
 13. The method according toclaim 11, further comprising the step of preparing for engagement,during the first upshift or the first downshift, the at least one shiftelement required for the successive upshift or the successive downshift,at a time which precedes the synchronous point of the first upshift orthe first downshift by one of a time-controlled and an event-controlledapplicable first time period.
 14. The method according to claim 13,further comprising the step of changing the at least one shift element,prepared to be engaged during the successive upshift or the successivedownshift, from a preparation phase to a shift phase at a time beforereaching the synchronization point of the first upshift or the firstdownshift, by a second time interval applied in another time-controlledmanner or another event-controlled manner.
 15. The method according toclaim 14, further comprising the step of delaying the step of changingthe at least one shift element, prepared to be engaged during thesuccessive upshift or the successive downshift, from the preparationphase to the shift phase, until the rapid filling phase of the at leastone shift element to be engaged during the successive upshift or thesuccessive downshift has been completed, if the time before reaching thesynchronization point of the first upshift or the first downshift andthe second time interval occurs before the end of a rapid filling phaseof the at least one shift element to be engaged during the successiveupshift or the successive downshift; or immediately changing the atleast one shift element to be engaged during the successive upshift orthe successive downshift from the preparation phase to the shift phase.16. The method according to claim 13, further comprising the step ofdelaying the preparation of the at least one shift element to be engagedduring the successive upshift or the successive downshift, until a rapidfilling phase of a first shift element to be engaged during the firstupshift or the first downshift has been completed, if a time, determinedfrom the synchronization point of the first upshift or the firstdownshift in progress and the first time period, occurs before the endof the rapid filling phase of the first shift element to be engagedduring the first upshift or the first downshift; and immediatelybeginning preparation of the at least one shift element to be engagedduring the successive upshift or the successive downshift.
 17. Themethod according to claim 13, further comprising the steps of preparingthe at least one shift element disengaging in the successive upshift orthe successive downshift while the first upshift or downshift is carriedout, for disengaging during the successive upshift or the successivedownshift at the beginning of the first upshift or downshift, andswitching the at least one shift element prepared for disengaging in thesuccessive upshift or the successive downshift from a preparation phaseto a shifting phase at the time that precedes the synchronous point ofthe first upshift or the first downshift by a time-controlled orevent-controlled applicable third time period.
 18. The method accordingto claim 11, further comprising the steps of requiring disengagement of,at most, two of the five shift elements and engagement of a remainder ofthe five shift elements, in each of a plurality of forward and reversegears for transferring torque and force; and one of increasing anddecreasing a torque of the drive motor, relative to a torque of thedrive motor derived from a driver's wish, during at least one of thefirst upshift or the first downshift and the successive upshift or thesuccessive downshift, to assist in overlapped implementation of thesuccessive upshift or the successive downshift.
 19. The method accordingto claim 18, further comprising the step of checking, during eachdownshift carried out and at a time, applicable in a time-controlledmanner or an event-controlled manner, whether a prepared follow-upshift, corresponds with a driver's wish to carry out further successivedownshifts during traction operation of the drivetrain, if no follow-upshift is desired, the prepared follow-up shift is discontinued and thetorque of the drive motor torque is reduced relative to the torque ofthe drive motor derived from the driver's wish, but if a follow-up shiftis desired, on the basis of the driver's wish, the prepared follow-upshift is carried out and the torque of the drive motor is not reduced.20. The method according to claim 18, further comprising the step ofincreasing the torque of the drive motor relative to torque of the drivemotor, derived from the driver's wish, during each downshift carried outand also checking, during each downshift carried out and at the timeapplicable in a time-controlled manner or an event-controlled manner,whether a prepared follow-up shift corresponds to the driver's wish, tocarry out a follow-up downshifts when the drivetrain is in a thrustoperation or a part-load traction operation, if the follow-up downshiftis desired, a ramp-like transition, is implemented between torque levelsof the follow-up downshifts, but if the follow-up shift is not desired,the prepared follow-up shift is discontinued and the torque of the drivemotor is discontinued to prevent the follow-up downshift.